Transport of liquid explosive nitric esters



TRANSPORT OF LIQUID EXPLOSIVE NITRIC ESTERS Filed Oct. 8, 1958 2 Sheets-Shedl l IrI Nov. 2l, 1961 R. BENTLEY ETAL 3,009,477

TRANSPORT oF LIQUID ExPLosIvE NITRIC EsTERs Filed Oct. 8, 1958 2 Sheets-Sheet 2 24 h\`x\\\"1l 5 so 29 2v Fre. 2.

31 43' 44 e1 41 4o se s? 34 I A@ f A Hnus wllunj/ United States Patent O 3,009,477 TRANSPRT F LIQUID EXPLOSIVE NTRIC ESTERS Roy Bentley, Largs, and Kenneth Ashbrooke Smith, West Kilbride, Scotland, assignors to Imperial Chemical Industries Limited, London, England, a corporation of Great Britain Filed Oct. 8, 1958, Ser. No. 765,965 Claims priority, application Great Britain Oct. 9, 1957 5 Claims. (Cl. 137-565) This invention relates to improvements in the transport of liquid explosive nitric esters, for example nitroglycerine, nitroglycol and diethylene glycoldinitrate, or mixtures thereof.

The invention has particular Aapplication to equipment wherein the liquid explosive ester is transported from one location to another such as from a wash house to a mixing house Where explosive compositions containing the nitric esters are being made. Itis usual to transport such liquids on the site by bogie. This method suifers from the disadvantage that it is not readily applicable to an automatically operated plant and the transport of liquid explosive nitric esters on the site through pipes has been considered. There is the hazard in transmitting liquid explosive nitric esters by pipeline that an explosion may be initiated `at any point and may be transmitted along the entire lengthof the pipe. Thisk hazard is well recognized and various methods have been adopted -to minimise it. The known methods include the transport of the explosive nitric ester as an emulsion with water, the alternation of columns of emulsion and of water in the pipe line, the provision of a number of syphoning arrangements of diierent capacities in the pipe line and other Ways. A general discussion of the problem is to be found in British Patent No. 746,826.

The present invention is applicable to a method and equipment in which an explosive nitric ester is transported by pipe line from one location to another in the form of an emulsion in water since it is safer to transport water emulsions of the esters than to transport the esters alone. It is known that hazardous conditions can arise if certain changes occur in the characteristics of the emulsion and the present invention resides in providing means adapted to come into operation upon the registration of a change in the condition of the `emulsion that is likely to render it unstable, to actuate a series of valves in the equipment so as to shut oit the ow of explosive ester to the emulsier and of emulsion to the separator and to introduce a ow of Water into the emulsion lines so that the pipeline system is washed free of hazardous explosive liquid.

In an application of the present invention nitroglycerine is conveyed from a container in a wash house to an emulsifier where it is emulsied with Water and thence the emulsion is transported by pipline to a mixing house located remotely from the wash house. The nitroglycerine is metered and pumped from its container in the wash house to the emulsier at a rate `appropriate to the rate at which the explosive composition is being mixed in the mixing house; at the same time water, is` metered of water to each part of nitroglycerine when the latter is flowing at maximum rate. The emulsion is then passed to the mixing house through a piping system. It has been held that there is a diameter of pipe for the conveyance of liquid nitric esters below which propagation of detonation does not occur. This characteristic is discussed in British Patent No. 746,826. The critical diameter of pipe for the transport of nitroglycerine emulsion is larger than that for nitroglycerine alone and, in accordance with the general principles referred to in British Pate-nt No. 746,826, it is recommended that small bore, preferably jointless, pipes of up to five eights of one inch (5/i) in diameter be employed for the transport of the nitroglycerine emulsions in water from one location to the other. Suitable pipes may be fashioned from a thermoplastic composition such as polyethylene. We believe this diameter of pipe to be suliicient to prevent the propagation of detonation at the temperatures encountered on the plant when normal emulsions of the type described are being transported and also to provide good turbulence when either water alone or nitroglycenine emulsion is owing. Whenever a fault occurs in any part of the system through which the nitroglycen'ne is owing, or into y 'which it is being introduced, provision is made for valves, which preferably are of a pneumatic type, to come into operation to stop the mixing process. The system is arranged so that, when valves operate, the feed of nitroglycerine stops and the water flow is diverted so that the emulsion lines are washed out by a turbulent flow of water until yall the emulsion has been transferred to the wash house tanks or otherwise suitably disposed.

Experimental evidence suggests that Water emulsions of the liquids referred to are more liable to detonation if the explosive liquid is in the continuous phase. It is known that small changes in conditions can cause the reversal of emulsions; for example, a change in stirring speed in a nitrator has been known to cause such a reyersal. The provision of suitable indicating means in the emulsion line, such as for example a conductivity type of probe, lallows such a reversalto be notified whereupon steps can be taken to stop the flow in the system and to iiush it out as previously described. The indicator may also detect faulty emulsions, due for example `to partial failure of the water supply, so as to allow suitable action to be taken to stop the flow of nitric ester emulsion and clean out the system.

In the accompanying drawings FIGURE l is a diagrammatic form-of equipment showing Ian application of the invention to the conveyance of a nitroglycerine emulsion from a wash house to a mixing house, and FIGURES 2, 3 and 4 are details of an emulsifying unit, a combined stop valve and pressure chamber and of a two-way valve respectively. A tank .1 contains a supply of nitroglycerine 2 which is delivered through pipes 3 and 4 to an'emulsi- Iier 5. 6 is a pump and metering system interposed between the pipes 3 and A4, which operates to meter and pump the nitroglycerine through the system at a rate appropriate to the rate of mixing in a mixer 7 located in the mixing house. 8 is a sto-p valve adapted, as hereinafter described, to come into oper-ation to shut oi the ilow of nitroglycerine to the emulsiiier 5l if a fault occurs in the emulsion lines. 9 is a water tank which receives water l from a separator 10; water may also be admitted from a 'mains supply. The Water circulates through a pipe 12 to a pump and metering unit 11 and thence through pipes 13 and 14 to the emulsier 5 where it is mixed and emulsied with the nitroglycerine entering through the pipe 4. The pipe -13 has a junction piece 15 at its head leading alternatively to a stop valve 16 and a two way valve 17. Valve 17 is normally closed and valve 16 open to the junction piece 15 so that the iiow of water is normally through the pipe 14. 18 is a two .vay valve interposed between the pipe 14 and pipes 23 and 19 leading respectively to the emulsifier and to a wash tank 20. The two-way valve 18 is set normally to direct the fiow through the pipe 23 to the emulsier but it is adapted to divert fiuid by way of a pipe 19 to a wash tank 20. The water is metered and pumped, through the pump and metering system 11, to the emulsifier 5 at a rate suicient to provide an emulsion consisting of at least two parts of water to one part of nitroglycerine when the latter is flowing at maximum rate. The nitroglycerine/water emulsion fiows from the emulsier 5 through one or more pipes 21 thence through the valve l17 and pipe 22 to a separator 1t) in the mixing house from which nitroglycerine is delivered to a mixer 7 and water is drawn off to the tank 9 for recycling in the system. When a fault develops in the system provision is made for the stop valves 8 and 16, which may be automatically operated, to close whereby the flow of nitroglycerine to the emulsier 5, and of water through the pipe 14, is stopped; at the same time the two way valves 17 and 18 are operated to direct water from pipe 13 through the junction head to the pipe system 21 so that the water fiows counter to the normal flow of the nitroglycerine/water emulsion thus washing the emulsion from the system back from the mixing house through the pipe system 23 and 19 by way of the two way valve 18 to the wash tank 2l). This ensures that within a short time after a breakdown the hazardous explosive nitric ester is cleaned out of the transfer system and removed from the vicinity of the mixing house.

A preferred form of the emulsifying unit 5 is indicated in FIG. 2 of the drawings. lThis unit has four plates 24 bolted together but separated by gaskets 25, which may be of neoprene or of silicone rubbers. Water and nitroglycerine enter the unit through respective opposed inlet ports 26 and 27 passing through a manifold 28 to a ceutral mixing chamber 29; the mixing chamber 29 may be formed by cutting a slot in the gasket which separates the two inner plates 24. The mixed liquids are emulsied in the chamber 29 by the turbulence caused by their ow velocity. Emulsion leaves the unit 5 through one or more exit ports 30. This emulsifier has the advantage over emulsiiiers of known type in having no moving parts so that hazards due to friction are reduced. It is preferred not to use commercial type valves because of the risk of initiation of the explosive ester by friction and FiGURE 3 indicates a form of the stop-valves 8 and 16 suitable for use with the present invention. The stop valve, as indicated in FIG. 3, has three plates 31, 32, 33. Plates 31 and 32 are separated by a gasket which forms diaphragms 34 and 43, suitably formed of neoprene or a silicone rubber and plates 32 and 33 are separated by a gasket 35 which 4may be also of neoprene or a silicone rubber. Liquid explosive ester enters the chamber 36 which communicates with a pressure chamber 37 through ports-38. 39 is an inlet for the admission of compressed air to the chamber 37 and 40 is an outlet for attachment of a tube leading to a gauge (not shown). 41 is an exhaust for the air brought in through the inlet 39. The pressure on the air side of the diaphragm is arranged to be at a relatively low figure (say 5 pounds per square inch); this can be arranged by the use of small bore tubing in the air conduit line. The pressure of the explosive liquid ester in the chamber 36 is sutiicient to cause the diaphragm 34'to cover the exhaust 41 until sufficient air pressure builds up in the chamber 37 to force the diaphragm 34 away from the exhaust 41; this causes the diaphragm to flutter over the exhaust so that the pressure transmitted through the outlet 40 to the gauge is the same as that of the explosive liquid ester. The explosive liquid ester passes from the chamber 36 along a channel 6() via ports 45 to a chamber 6l and exits from the unit at 42. 43 is a diaphragm valve which, when connected by way of an inlet 44 with a supply of high pressure fluid, for example air, forces the diaphragm against the liquid ester conduit ports 4-5 to shut ofi the liquid ester flow; remote or automatic operation may be adopted using known means for this purpose.

FIGURE 4 indicates a suitable form of pneumatically operated two way valve having plates 46, 47 and 48 separated respectively by diaphragms 49 and 51 and a gasket 50. Fluid enters the valve at 52 and proceeds by way of a manifold 53 either to exit 54 or exit 55. The selection of the exit is regulated by the supply of iiuid pressure either through the inlet 56 or the inlet 57 to cause the diaphragm 49 or the diaphragm 51 to close the delivery ports 58 or 59 thus closing off delivery either to exit 54 or exit 55 so that fluid, passing through the two way valves 17 and 18 may be routed at will through alternative paths.

What we claim is:

1. In the transport of liquid explosive nitric ester, an apparatus for reducing the hazard in the transpont of the resulting emulsion by providing backward flushing thereof comprising: an emulsier devoid of moving parts and having a first inlet port for the admission of nitric ester, a second inlet port for admission of water, a manifold communicating with said inlet ports, means providing a mixing chamber communicating with said manifold, emulsion outlet means communicating with said mixing chamber; a separator; a first and a second 2-way valve, each of said valves having three ports therein and having passage means for selectively connecting the second port of each valve with either the first or third ports thereof; the first and second ports thereof being in normal communication when the system is discharging emulsion to said separator; means for supplying nitric ester to said first emulsifier inlet port including stop valve means therein; means providing communication between said second port in said first 2- way valve, and said second emulsifier inlet port, means providing communication between said first 2-way tirst inlet port and said third port in said second l-way valve, said last-mentioned means further providing stop valve means ytherein and a water supply line upstream from said stop valve means, said water supply line including water pump means; means providing communication between said emulsier outlet means and said second port of said second 2-way valve, and between said first port of said last-mentioned valve to said separator; a receiver; means providing communication between the `third port of said first 2-way valve and said receiver, whereby the water normally fiows from said water pump means through said water supply line, through said water shut-off valve, through said first 2way valve and into said emulsifier; the emulsion flowing from said emulsiiier through said second 2-way valve to said separator, and when said shut-off valves are closed and said 2-way valves provide communication between said second and third ports, the water will iiow through said second 2-way valve, through said emulsifier, through said rst 2-way valve, and to said receiver, thereby providing a backwash of the emulsion.

2. Apparatus as defined in claim 1 wherein each of said 2-way valves includes inlet means, means providing a `passage communicating therealong with said inlet means, rst aud second outlet manifold means communicating with said passage at each end thereof; diaphragm means cooperating with each of said outlet manifold means, meansffor supplying pressure to said diaphragm means to close the portion of said passage communicating with its outlet manifold means.

3. Apparatus as defined in claim 1 wherein said stop valve means includes an inlet port, a manifold chamber communicating therewith, an outlet port and a manifold chamber communicating therewith, a passage providing communication between said manifold chambers, diaphragm means cooperating with each manifold chamber, means for supplying pressure to said diaphragm means whereby ythe passage becomes closed.

4. The structure defined in claim 1 wherein said mixing cham-ber is in the form of a narrow channel.

5. The structure dened in claim 1 wherein the internal diameters of the uid lines do not exceed about 16 mm.

References Cited in the le of this patent UNITED STATES PATENTS Maxim Apr. 7, 1891 y Warner Feb. 19, 1918 Meissner Mar. 26, 1940 Crater Nov. 28, 1944 Mueller June 13, 1950 

1. IN THE TRANSPORT OF LIQUID EXPLOSIVE NITRIC ESTER, AN APPARATUS FOR REDUCING THE HAZARD IN THE TRANSPORT OF THE RESULTING EMULSION BY PROVIDING BACKWARD FLUSHING THEREOF COMPRISING: AN EMULSIFIER DEVOID OF MOVING PARTS AND HAVING A FIRST INLET PORT FOR THE ADMISSION OF NITRIC ESTER, A SECOND INLET PORT FOR ADMISSION OF WATER, A MANIFOLD COMMUNICATING WITH SAID INLET PORTS, MEANS PROVIDING A MIXING CHAMBER COMMUNICATING WITH SAID MANIFOLD, EMULSION OUTLET MEANS COMMUNICATING WITH SAID MIXING CHAMBER, A SEPARATOR, A FIRST AN A SECOND 2-WAY VALVE, EACH OF SAID VALVES HAVING THREE PORTS THEREIN AND HAVING PASSAGE MEANS FOR SELECTIVELY CONNECTING THE SECOND PORT OF EACH VALVE WITH EITHER THE FIRST OR THIRD PORTS THEREOF, THE FIRST AND SECOND PORTS THEREOF BEING IN NORMAL COMMUNICATION WHEN THE SYSTEM IS DISCHARGING EMULSION TO SAID SEPARATOR, PORT INCLUDING STOP VALVE MEANS THEREIN, MEANS PROVIDING COMMUNICATION BETWEEN SAID SECOND PORT IN SAID FIRST 2WAY VALVE, AND SAID SECOND EMULSIFIER INLET PORT, MEANS PROVIDING COMMUNICATION BETWEEN SAID FIRST 2-WAY FIRST INLET PORT AND SAID THIRD PORT IN SAID SECOND 2-WAY VALVE, SAID LAST-MENTIONED MEANS FURTHER PROVIDING STOP VALVE MEANS THEREIN AND A WATER SUPPLY LINE UPSTREAM FROM SAID STOP VALVE MEANS, SAID WATER SUPPLY LINE INCLUDING WATER PUMP MEANS, MEANS PROVIDING COMMUNICATION BETWEEN SAID EMULSIFIER OUTLET MEANS AND SAID SECOND PORT OF SAID SECOND 2-WAY VALVE, AND BETWEEN SAID FIRST PORT OF SAID LAST-MENTIONED VALVE TO SAID SEPARATOR, A RECEIVER, MEANS PROVIDING COMMUNICATION BETWEEN THE THIRD PORT OF SAID FIRST 2-WAY VALVE AND SAID RECEIVER, WHEREBY THE WATER NORMALLY FLOWS FROM SAID WATER PUMP MEANS THROUGH SAID WATER SUPPLY LINE, THROUGH SAID WATER SHUT-OFF VALVE, THROUGH SAID FIRST 2-WAY VALVE AND INTO SAID EMULSIFIER, THE EMULSION FLOWING FROM SAID EMULSIFIER THROUGH SAID SECOND 2-WAY VALVE TO SAID SEPARATOR, AND WHEN SAID SHUT-OFF VALVES ARE CLOSED AND SAID 2-WAY VALVES PROVIDE COMMUNICATION BETWEEN SAID SECOND AND THIRD PORTS, THE WATER WILL FLOW THROUGH SAID SECOND 2-WAY VALVE, THROUGH SAID EMULSIFIER, THROUGH SAID FIRST 2-WAY VALVE, AND TO SAID RECEIVER, THEREBY PROVIDING A BACKWASH OF THE EMULSION. 